Electrolytic measurement systems employ probes having electrodes which are immersed in a fluid for measuring the electrical conductivity thereof. Such probes are often immersed in sewage or industrial effluents having chemical substances which react under the influence of electric fields within the probe to produce electrochemical encrustations upon the electrodes as well as upon a metallic shield or a case which may be used to shape the electric fields and control ground currents to permit a more precise measurement of the fluid characteristics. For example, in the case of a saline solution, the electrical conductivity of the fluid is a measure of the concentration of ions in solution.
There are two problems that are frequently encountered in the measurement of the electrical conductivity of fluids. First, particularly in the case of raw sewage, there is a tendency for probes immersed in the sewage to clog because of hairs, threads, and other vegetable and animal matter which may become entrapped in the probe and prevent the passage of fluid therethrough. Secondly, the aforementioned electrochemical by-products tend to precipitate on the surfaces of the electrodes and introduce an electrode resistance thereto with the result that the distribution of electric fields between individual ones of the electrodes as well as between the electrodes and the shield is altered. Furthermore, the electrode resistance induced by the encrustation alters the magnitudes of currents flowing through the fluid with a resultant loss of calibration of the measurement system.